Compositions for removing metal ions from aqueous process solutions and methods of use thereof

ABSTRACT

The present invention provides a composition and process using the composition for removing metal ions from aqueous process solutions. These compositions include a non-metallic compound entrapped within or supported onto a substrate. In one embodiment, the non-metallic compound is a thiuram. In another embodiment, the compositions further include non-metallic compound that is a dithiocarbamate. These compositions are contacted with the metal ions in the aqueous process solution to form an organometallic complex precipitate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/945,685, filed Sep. 21, 2004, and entitled, “Compositions forRemoving Metal Ions from Aqueous Process Solutions and Methods of UseThereof,” which is a divisional of U.S. patent application Ser. No.10/211,406, filed Aug. 1, 2002, and entitled “Compositions for RemovingMetal Ions from Aqueous Process Solutions and Methods of Use Thereof,”which issued as U.S. Pat. No. 6,818,135, which claim priority to U.S.provisional patent application Nos. 60/309,836, 60/309,837 and60/309,854, all filed on Aug. 3, 2001, which are all incorporated hereinby reference in their entirety.

FIELD OF INVENTION

The present invention describes a composition and process using thecomposition for removal of metal ions from aqueous process solutions.

BACKGROUND OF THE INVENTION

Various metals are used in many useful industrial processes. Forexample, silver is used in many image-forming industrial processes, suchas photography, thermography, and photothermography. Such processes,however, result in waste solutions containing metal ions at levels thatmay be undesirable to the environment. In addition, many countries nowhave laws that control the levels of certain metal ions that can bereleased into the environment. Since commercial disposal of largevolumes of untreated waste solutions can be costly, there has been aconcerted effort to treat the waste solutions in a cost effectivemanner. Furthermore, these metals can be of sufficient value to justifytheir recovery.

Metals have been removed from aqueous waste solutions utilizingprocesses such as ion exchange, electrolysis, and settling. However, allof these known processes have their limitations. Ion exchange is costly,slow and impractical. The ion exchange resins are expensive because theyrequire complex and sophisticated fabrication processes. Some of thiscost can be recouped by regenerating the ion exchange resins. However,the waste solutions produced during regeneration typically have to betreated. Similarly, electrolysis is also costly due to maintenance,resource requirements, and energy input. Electrolysis is also verysensitive to contaminants and generally provides ineffective levels ofmetal recovery.

Settling processes typically use one or more agents that transform themetals into materials that are no longer soluble in the system andsettle to the bottom of the tank. However, currently known settlingprocesses have the following limitations. Undesirably large amounts ofsludge, which cannot be regenerated, can be formed. Some settlingprocesses require heating to very high temperatures, e.g., greater than80° C., to provide useful results. Still others require the use of achange in pH to cause the transformation of the metal into an insolublematerial.

Accordingly, there is a need for effective recovery of metal ions fromaqueous waste solutions (hereafter also referred to as aqueous processsolutions).

SUMMARY OF THE INVENTION

The present invention is directed to a composition and the use of thecomposition in a process that effectively removes metal ions fromaqueous process solutions.

The composition includes a non-metallic compound, which is capable offorming a complex with a metal ion, entrapped within or supported onto asupport material. In one embodiment of the present invention thenon-metallic compound is a thiuram. In another embodiment of thecomposition, the composition further includes a dithiocarbamateentrapped within or supported onto the support material. Thesecompositions can be obtained by a process of contacting a non-metalliccompound composition with a support material. The non-metallic compoundcomposition can include the thiuram or a combination of thiuram anddithiocarbamate. The present invention is also directed to thecomposition obtained by this process.

In another aspect of the present invention, a process is disclosed forremoving metal ions from an aqueous process solution utilizing thecompositions of the present invention. The process includes reacting themetal ions in the aqueous process solution with a treatment compositionhaving a non-metallic compound entrapped within or supported onto asupport material. The metal ions and the non-metallic compound can forman organometallic complex. It is preferred to have a wetting agentpresent in the aqueous process solution.

The present invention is also directed to a product, an organometalliccomposition, obtained from the processes described above. Theorganometallic composition includes an organometallic complex entrappedwithin or supported onto a support material, wherein the organometalliccomplex includes a non-metallic compound associated with a metallic ion.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides treatment compositions and processesusing the compositions for removing metal ions from aqueous processsolutions. The present invention also provides novel organometalliccomplexes resulting from the processes. The term “aqueous processsolution,” as used herein, means any liquid containing from about 1 ppmto about 15,000 ppm of metal ions. The term “about,” as used herein,means plus or minus 10% of the referenced value. The term “aqueous”, asused herein, means containing greater than about 50%, by weight of thesolution, of water or a water miscible solvent. The processes usedherein for aqueous process solutions can also be used for appropriategaseous process mixtures. Nonlimiting examples of aqueous processsolutions include the processing solutions from the followingtechnologies: photography, photothermography, thermography, lithography,metallurgy, semiconductor polishing, and x-ray imaging. The term “metalion,” as used herein, means the soluble form of any metal in Groups IBthrough VIIB and VIII of the periodic table (according to CRC Handbookof Chemistry and Physics, 62nd Edition, 1981-1982), including theelements having the atomic numbers of 58-71 and 90-103, aluminum,gallium, indium, thallium, germanium, tin, lead, antimony, bismuth,mixtures thereof, and alloys thereof. Metal ions of particular interestare those identified in the Resource Conservation Recovery Act (RCRA).Metal ions are preferably selected from the group consisting of arsenic,barium, cadmium, chromium, cesium, copper, iron, lead, mercury, nickel,selenium, silver, technetium, thallium, zinc, actinides, lanthanides,mixtures thereof, and alloys thereof.

The treatment compositions of the present invention include anon-metallic compound that is entrapped within and/or supported onto asupport material. Typically, the treatment composition includes fromabout 5% to 60%, preferably from about by 20% to about 40%, by weight ofthe composition, of a non-metallic compound, which can associate with ametal ion, and from about 40% to about 95%, preferably from about 60% toabout 80%, by weight of the composition, of a support material. Thenon-metallic compound is preferably not a polymer.

Without wanting to be limited by any one theory, it is believed that thenon-metallic compounds of the present invention form an organometalliccomplex with the metal ion. Since the non-metallic compound is entrappedwithin and/or supported onto the support material, the resultingorganometallic complex is also entrapped within and/or supported ontothe support. When the treatment composition reaches a level ofunacceptable performance, e.g., when the most of the non-metalliccompound has been converted to the organometallic complex, the treatmentcomposition can simply be replaced. The spent treatment composition canthen be further processed, as described in greater detail below.

In one embodiment of the present invention, the treatment compositionsof the present invention include a non-metallic compound that is athiuram, which can also be referred to as thiram. Thiuram is sparinglysoluble in the aqueous process solution. The term “sparingly soluble,”as used herein, means that less than 0.1% by weight of the material issoluble in the aqueous process solution. One group of thiurams can becharacterized by the general chemical formula (I), as illustrated below.

wherein, m is an integer of 1 or 2; and R₁, R₂, R₃, and R₄ areindividually selected from the group consisting of C1-C10 linear alkyls,C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls. As is well known to the skilled artisan, any of thecarbon atoms or hydrogen atoms in each of the above described R-groupscan be substituted with chemical moieties that tailor the performance ofthe non-metallic compound without significantly effecting the requisitesolubility properties.

Examples of useful non-metallic compounds of formula (I) include, butare not limited to, tetramethylthiuram monosulfide (CAS# 97-74-5);bis(dimethyldithiocarbamoyl)disulfide (CAS# 137-26-8);tetrabenzylthiuram disulfide (CAS# 10591-85-2); tetraethylthiuramdisulfide (CAS# 97-77-8); tetrabutylthiuram disulfide (CAS# 1634-02-2),dipentamethylenethiuram tetrasulfide (CAS# 120-54-7), and mixturesthereof.

In another embodiment of the present invention, the treatmentcompositions of the present invention further include a water solublenon-metallic compound that is a dithiocarbamate. One group ofdithiocarbamates can be characterized by the general chemical formula(II), as illustrated below.

wherein, n is an integer of 1 or 2; o is an integer of 1 or 2; R₅ and R₆are individually selected from the group consisting of C1-C10 linearalkyls, C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls; and Y is an element selected from Groups IA and IIAof the periodic table. As is well known to the skilled artisan, any ofthe carbon atoms or hydrogen atoms in each of the above describedR-groups can be substituted with moieties that enhance the performanceof the non-metallic compound.

Examples of useful non-metallic compounds of formula (II) include, butare not limited to, sodium dimethyldithiocarbamate (CAS# 128-04-1),sodium diethyldithiocarbamate (CAS# 148-18-5), sodiumdibenzyldithiocarbamate (CAS# 55310-46-8), sodium dibutyldithiocarbamate(CAS# 136-30-1), and mixtures thereof.

The above-described non-metallic compounds are entrapped within and/orsupported onto a support material. Any water insoluble material can beused as the support material. The term, “water insoluble material,” asused herein, means that the material does not substantially dissolve inwater. Accordingly, the support can be made of a hydrophilic material solong as the material does not substantially dissolve in water. Thesupport is preferably made of a material that is capable of entrappingthe non-metallic compound. More preferably, the support material iscapable of entrapping the non-metallic compound and in an orientationthat allows the active groups, e.g., the sulfur groups, to be availablefor association with the metal ions in the aqueous process solution.Accordingly, it is believed that support materials having cavities withhydrophobic characteristics are preferred for non-metallic compoundshaving hydrophobic R-groups. General examples of useful supportmaterials include, but are not limited to, natural and syntheticpolymers, organic compounds, inorganic compounds, and mixtures thereof.

Examples of useful polymers include, but are not limited, polyolefinpowders and sheets, such as nylon, polyester, polyethylene,polypropylene, polycarbonate, polystyrene, polyacrylate, benzoguanamineresin, polytetrafluoroethylene, distyrene-benzene polymer, epoxy resin,and acrylic resin; and natural polymers, such as fine crystallinecellulose and polysaccharides. Particle sizes can be chosen to optimizefluid flow through the support material. One class of polymers that arealso useful are natural and synthetic resins, that are polymericmaterials having functional moieties that can be tailored to createaffinity for certain types of compounds. Examples of useful resinsinclude, but are not limited to, chelating resins, ion exchange resins,such as cationic or cationic resins; and resins used for watertreatment, e.g., those having a styrene-divinylbenzene backbone (whichare commercially available from Rohm and Haas Company as Ambersorb 563,Ambersorb 572, Amberlite IRC 718 and Amberlite XAD4). Such resins areavailable in powder, bead, and sheet forms.

Examples of useful organic compounds include, but are not limited to,carbon, granular activated carbon, nut shells, husks, stalks, wood andother sources of natural cellulose. The compounds can typically be usedin granular forms, e.g., in 4/20, 12/40, and 20/50 mesh sizes.

Examples of useful inorganic compounds include, but are not limited to,metal oxides, such as silicon dioxide and titanium oxide; naturalzeolite and synthetic zeolite; talc; kaolin; sericite; bentonite;muscovite; phlogopite; lepidolite; biotite; synthetic golden mica;vermiculite; diatomateous earth; magnesium silicate; calcium silicate;aluminum silicate; barium silicate; metallic tungustates; silica;hydroxylapatite; boron nitride; and ceramic powders.

The treatment compositions of the present invention can be obtained bycontacting a non-metallic compound composition with a water insolublesupport material in a liquid that is non-reactive. The non-metalliccompound composition includes one or more of the above-describednon-metallic compounds. Typically the liquid that is used is water,because of environmental and cost factors. When the support material isin the form of sheets, the non-metallic compound can also be paintedonto the surface. Although the non-metallic compound can be absorbedinto the support at a wide variety of process parameters, the rate ofabsorption can be enhanced by conducting the reaction with mixing at atemperature from about 0° C. to about 120° C. at standard pressures, andpreferably from about 20° C. to about 100° C. After the absorptionprocess is complete, the resulting treatment composition can be dried.

The present invention is also directed to a method or process ofutilizing the treatment compositions of the present invention to removemetal ions from aqueous process solutions. Treated aqueous processsolutions can have less than about 10 ppm, preferably less than about 5ppm, and more preferably less than about 0.10 ppm of metal ions.Essentially, this process involves reacting the treatment compositioncontaining the non-metallic compound with the aqueous process solutioncontaining the metal ion. As discussed previously, it is believed thatthe metal ions react with the non-metallic compound to form anorganometallic complex. It is believed that the organometallic complexis in the form of a precipitate that is entrapped in or supported on thesupport material.

It has been surprisingly found that the processes of the presentinvention can effectively remove metal ions to these low levels even inthe presence of high concentrations of chelators. Chelators aretypically used to maintain the metal ions in the process solution,thereby hindering their removal. The present process can be utilized toeffectively remove metal ions in process solutions having chelator tometal ion numeric proportions of greater than about 500:1. In fact, thepresent process can also be effective in any of the following chelatorto metal ion numeric proportions: from about 1,250,000:1 to about 10:1;from about 500,000:1 to about 20:1; and from about 100,000:1 to about100:1.

It is also preferable for the aqueous process solution to have a wettingagent in a concentration from about 0.01 molar to 10 molar, morepreferably from about 0.025 molar to 0.5 molar, and most preferably fromabout 0.05 molar to 0.25 molar. Some process solutions may already havea wetting agent as a component of the waste stream. For example,photographic waste solutions typically contain wetting agents insufficient concentration. If the aqueous process solution does notcontain a wetting agent, an appropriate amount of a wetting agent may beadded. Wetting agents, also known as surfactants, are compounds thatreduce the surface tension of liquids, or reduce interfacial surfacetension between two liquids or a liquid and a solid. It is, therefore,believed that the wetting agent helps to lower the barrier of reaction.Wetting agents may be soluble in both organic and water solutions.However, it is preferred that the wetting agents used herein be at leastsoluble in the aqueous solution at the concentrations used. Generalcategories of useful wetting agents include, but are not limited to,non-ionic surfactants, anionic surfactants, cationic surfactants,carboxylic acids, alcohols, and amines. Zwitter-ionic and amphotericsurfactants may also be useful. Examples of useful wetting agents aredisclosed in the Kirk-Othmer Encyclopedia of Chemical Technology (JohnWiley and Sons, New York), U.S. Pat. No. 6,399,676 issued to Labude, etal. on Jun. 4, 2002, and U.S. Pat. No. 6,087,312 issued to Masotti, etal on Jul. 11, 2000, all of which are incorporated herein by referencein their entirety. Examples of useful wetting agents include, but arenot limited to, acetic acid, propanoic acid, methanol, ethanol,propanol, tetraethyl ammonium hydroxide, fatty acids and salts thereof,alkylaryl sulfonates, and mixtures thereof.

The present process can be conducted at wide variety of reactionvariables, which can be tailored for optimization accordingly to anyparticular process. As in any chemical reaction, increasing the reactionor retention time, i.e., duration of physical contact of thenon-metallic compound and the aqueous process solution, is beneficial toincreasing the quantity and size of the precipitated organometalliccomplex. Accordingly, it is preferred to maximize the reaction orretention time as much as allowable taking into consideration otherprocess and economic variables. Typically, the reaction or retentiontime is at least 0.1 hours, preferably from about 0.1 hours to about 125hours, and more preferably from about 0.1 hours to about 12 hours. As iswell understood by the skilled artisan, lower reaction or retentiontimes can be needed at higher reaction temperatures.

The reaction can be conducted at a wide range of temperatures.Preferably, the reaction temperature is less than or equal to about 50°C., more preferably less than or equal to about 45° C., and mostpreferably at ambient temperatures. Ambient temperatures, as usedherein, means the normal temperature range of the surroundingenvironment, which typically can range about from 5° C. to about 40° C.The processes of the present invention, therefore, can be conducted withlittle or no heating, thereby decreasing the cost of heat inputs to thesystem. However, a small amount of heating to achieve reactiontemperatures within the above ranges may be desirable to achieve optimumprocessing results.

Lastly, the present process can be conducted at a wide range of pH's,especially if the process is conducted in a substantially oxygen-freeenvironment. However, due to the increased possibility of organicmaterials being degraded by oxidized metal ions in oxygen richenvironments, e.g., Fenton's reaction, it is preferred to conduct theprocess at a pH of greater than or equal to about 3.0, preferably fromabout 4.0 to 12.0, and more preferably from about 7.0 to 12.0. It isalso believed that the present processes provide better separation ofmetal ions at lower surface tensions, e.g., at about the surface tensionof 1% by weight of acetic acid in water.

In one embodiment of the present invention, the process involvesintroducing the treatment compositions of the present invention to theaqueous process solution in batch or continuous systems. Such systemscan be run in parallel and/or in series. Such systems typically utilizea container, such as a tank, containing the aqueous process solution,and the container is adapted to provide mixing, e.g., by utilizing anymixing technology known to the skilled artisan. The treatmentcomposition is added in a concentration that is proportion to the metalions present in the aqueous process solution. In this embodiment, thetreatment composition is added such that the non-metallic compound ispresent at a concentration of from about 100.0:1.0 to about 10.0:1.0,preferably from about 75.0:1.0 to about 20.0:1.0, and more preferablyfrom about 60.0:1.0 to about 40.0:1.0 by molar ratio of the non-metalliccompound to the metal ions present in the aqueous process solution. Somenon-metallic compounds can even be effective at metal concentrationlevels of 1 ppm or less. More of the non-metallic compound may be neededat lower pH's, e.g., below about pH 4, in oxygen rich environments andwhen higher levels of contaminants are present, e.g., greater than about5 ppm. Contaminants are any chemical compounds other than the metal ionsand water.

When the removal of the metal ions reaches an unacceptable level, thespent treatment composition is simple replaced with a fresh one. Theentrapped organometallic precipitate can then be further processed, asdescribed hereinafter.

In another embodiment of the present process, the aqueous processsolution containing the metal ions can be introduced to a bed of thetreatment composition containing the non-metallic compound. In thisembodiment, a reaction bed is packed with the treatment composition, anda flow of aqueous process solution is controlled through the bed viagravity or positive pressure to optimize the reaction or retention timeof reaction in relation to other process and economic variables. Thereaction bed can be in any acceptable geometric form. Typically, 1 moleof metallic ions will require about 50 moles of non-metallic compound,incorporated in a support material. More of the non-metallic compoundmay be needed at lower pH's, e.g., below about pH 4, in oxygen richenvironments and when higher levels of contaminants are present, e.g.,greater than about 5 ppm. The treatment composition in the reaction bedcan be replaced when removal of metal ions has reached an unacceptabledegree. The resulting precipitate entrapped in the support material canthen be further processed, as described hereinafter.

Optional ingredients known to the skilled artisan can also be used toaid in or optimize any of the process steps described above. Forexample, flocculating agents can be used to aid in the settling process.Nonlimiting examples of flocculating agents include acrylates. Also,antifoaming agents can also be used in the mixing step, assuming thatthe degree of agitation is not changed. Nonlimiting examples ofantifoaming agents include silicone oils.

As is well understood by the skilled artisan, the processes of thepresent invention can be used in conjunction with other conventionallyknown metal ion recovery systems, such as photochemical developer,fixer, and bleach-fix processing solutions involve metallic replacement,electrolytic recovery, chemical precipitation, ion exchange and reverseosmosis. For example, the aqueous process solution can first be treatedelectrolytically before the present process is used. Alternatively, thepresent process can be used first before electrolytic treatment.

As described above, it is believed that the non-metallic compounds ofthe present invention react with metal ions to form an organometalliccomplex. Without wanting to be limited by any one theory, it is believedthat the metallic ion associates to one or more sulfur groups on thenon-metallic compound via van der Waals forces, ionic forces, and/ordelta bonds. The entrapped organometallic complex can, therefore, befurther processed to recover the metal ions as native metal by removingthese attractive forces by any method known to the skilled artisan.Alternatively, the complexed non-metallic compound can simply be removedby any method known to the skilled artisan. Examples of suitable removaltechniques include, but are not limited to, oxidization, degradation,acidification, and flame refining.

EXAMPLES Example 1 Synthesis of Granular Activated Carbon SupportedTreatment Compositions

In a stainless steel container, about 716 grams ofbis(dimethyldithiocarbamoyl)disulfide (CAS# 137-26-8) in powder form wasadded to about 1234 grams of 12/40 mesh granular activated carbon (GAC)derived from coconut shells. The container was filled with water andheated to reflux at about 100° C. The reaction was continued until thebis(dimethyldithiocarbamoyl)disulfide was no longer visible, and theappearance of the support material is similar to GAC in water, i.e.,black in color. The reaction can typically be completed in about 12 toabout 16 hours, depending on the amount of agitation. The water can thenbe removed to obtain the GAC supported treatment composition.

Example 2 Use of the Treatment Composition in a Column

The treatment composition obtained from Example 1 can be used in a fixedbed reactor, such as a column. Using a column as an example, the columnhousing may be in the form of a tube with proper connections at bothends to allow the aqueous process solution to enter and exit the columnwhile maintaining the treatment composition in the column. Once thetreatment composition is added to the column, the aqueous processsolution can be slowly pumped into the column. This embodiment canprovide treated solutions containing less than about 0.05 ppm of silverions by adjusting the flow rate. Adjustment of the flow rate cancompensate for other factors that can effect performance, such as theinitial silver ion concentration, pH, and other metal ions.

A GAC supported treatment composition according to Example 1 was used toremove silver ions from a photochemical fixer solution having silverions at a concentration of from about 50 to about 80 ppm. The experimentwas conducted at a pH of about 7 and at a reaction temperature of about20° C., as follows. About 25 pounds of a GAC supported treatmentcomposition according to Example 1 was placed in a column having avolume of about 4 gallons. As is well known to the skilled artisan, the4-gallon column can be replaced with four 1-gallon columns placed inseries, or any combination to total the 4-gallon column. About 200gallons of the photochemical fixer solution was then steadily pumpedthrough the column at a rate of one gallon per hour. The retention timewas about 4 hours. The treated aqueous solution was tested for silverions using a Perkin Elmer flame atomic absorption spectrometer. Theprocedure for using such atomic absorption spectrometers to obtainconcentrations of metal ions is well known in the art. The treatedaqueous solution contained less than about 0.05 ppm of silver ions.

1. A composition for removing metal ions from an aqueous processsolution, the composition comprising a monomeric non-metallic compound,which comprises a thiuram, entrapped within or supported onto a supportmaterial, wherein the non-metallic compound is capable of forming acomplex with a metal ion in an aqueous process solution.
 2. Thecomposition according to claim 1, wherein the thiuram is characterizedby the general chemical formula (I),

wherein, m is an integer of 1 or 2; and R₁, R₂, R₃, and R₄ areindividually selected from the group consisting of C1-C10 linear alkyls,C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls.
 3. The composition according to claim 2, whereinthe thiuram is selected from the group consisting of tetramethylthiurammonosulfide, bis(dimethyldithiocarbamoyl)disulfide, tetrabenzylthiuramdisulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide,dipentamethylenethiuram tetrasulfide, and mixtures thereof.
 4. Thecomposition according to claim 1, wherein the non-metallic compoundfurther comprises a dithiocarbamate entrapped within or supported ontothe support material.
 5. The composition according to claim 4, whereinthe dithiocarbamate is characterized by the general chemical formula(II),

wherein, n is an integer of 1 or 2; o is an integer of 1 or 2; R₅ and R₆are individually selected from the group consisting of C1-C10 linearalkyls, C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls; and Y is an element selected from Groups IA and IIAof the periodic table.
 6. The composition according to claim 5, whereinthe dithiocarbamate is selected from the group consisting of sodiumdimethyldithiocarbamate, sodium diethyldithiocarbamate, sodiumdibenzyldithiocarbamate, sodium dibutyldithiocarbamate, and mixturesthereof.
 7. The composition according to any of claims 4, wherein thesupport material is selected from the group consisting of natural andsynthetic polymers, organic compounds, inorganic compounds, and mixturesthereof.
 8. An organometallic composition, comprising: an organometalliccomplex entrapped within or supported onto a support material, whereinthe organometallic complex comprises a monomeric non-metallic compound,which comprises a thiuram, associated with a metallic ion in an aqueousprocess solution.
 9. The composition according to claim 8, wherein thethiuram is characterized by the general chemical formula (I),

wherein, m is an integer of 1 or 2; and R₁, R₂, R₃, and R₄ areindividually selected from the group consisting of C1-C10 linear alkyls,C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls.
 10. The composition according to claim 9, whereinthe thiuram is selected from the group consisting of tetramethylthiurammonosulfide, bis(dimethyldithiocarbamoyl)disulfide, tetrabenzylthiuramdisulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide,dipentamethylenethiuram tetrasulfide, and mixtures thereof.
 11. Thecomposition according to claim 8, wherein the non-metallic compoundfurther comprises a dithiocarbamate.
 12. The composition according toclaim 11, wherein the dithiocarbamate is characterized by the generalchemical formula (II),

wherein, n is an integer of 1 or 2; o is an integer of 1 or 2; R₅ and R₆are individually selected from the group consisting of C1-C10 linearalkyls, C3-C10 branched alkyls, C3-C10 cyclo-alkyls, and substituted andunsubstituted aryls; and Y is an element selected from Groups IA and IIAof the periodic table.
 13. The composition according to claim 12,wherein the dithiocarbamate is selected from the group consisting ofsodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodiumdibenzyldithiocarbamate, sodium dibutyldithiocarbamate, and mixturesthereof.
 14. The composition according to any of claims 8 or 9, whereinthe support material is selected from the group consisting of naturaland synthetic polymers, organic compounds, inorganic compounds, andmixtures thereof.
 15. The composition according to any of claims 8 or 9,wherein the metal ion is selected from the group consisting of arsenic,barium, cadmium, chromium, cesium, copper, iron, lead, mercury, nickel,selenium, silver, technetium, thallium, zinc, actinides, lanthanides,mixtures thereof, and alloys thereof.